The NBA's Christmas Day schedule has evolved dramatically over the last couple of years. Traditionally, there has been a marquee game or two, which expanded to three a year ago. This season, the league has taken its holiday lineup to the next level, scheduling five full games. Here on the West Coast, it's possible to watch games essentially all day long. Basketball Prospectus previews all the action.

I've always linked the Hornets and Magic in my mind since writing a column identifying them both as contenders early last season, so it seems fitting to see them match up. Both teams entered this season battling the Plexiglass Principle--the tendency of teams to regress to the mean, which is one reason why teams that make large single-season improvements often go backwards the following year. Not so here; Orlando's point differential is actually up from a year ago, while New Orleans has slipped almost imperceptibly.

With due respect to the other contenders (Houston, Portland and Utah, notably), this could be described as a battle for the coveted role of the biggest threat to the triumvirate of Boston, Cleveland and the L.A. Lakers. Were it not for what those teams have done, the Magic in particular would be getting more attention as hot starters. Offensively, there are some similarities in what these two teams like to do. Both have excellent point guards who like to run pick-and-rolls, often finished by alley-oop lobs, with their centers. Both surround those pick-and-rolls with excellent shooters. The gap is at the defensive end, where Dwight Howard anchors a defense as stingy as almost any in the league. Beyond Howard, Orlando's other key players aren't known for their defense, so Stan Van Gundy deserves a lot of credit for a scheme that minimizes their weaknesses defending one-on-one.

A rematch of last year's opening-round series features two teams that have slipped a notch in the Western Conference race this year. While the Spurs' record exceeds their point differential, being in the thick of the battle for home-court advantage at this point is impressive given the time they played without All-Star guards Manu Ginobili and Tony Parker.

Their absence may have helped San Antonio integrate newcomers Roger Mason and George Hill, who offer additional athleticism on the perimeter to go with the shooting ability that is a must in the Spurs' system. With Mason and Hill taking minutes from Bruce Bowen, San Antonio's defense has suffered; the early-season woes at that end proved to be a fluke, but the Spurs are still a distant eighth in Defensive Rating and winning as much with their offense and their shooters as with their defense.

The addition of Jason Richardson seems to have the Suns playing more like their Seven Seconds or Less predecessors. The sample size is small, but in four games with Richardson in the lineup Phoenix is playing at a pace of 93.1 possessions per 48 minutes, up from their season mark, and scoring at a ridiculous rate of 121.1 points per 100 possessions. So save the remarks lamenting the demise of the Suns' offense; Phoenix has actually dropped off defensively in the transition from Mike D'Antoni to Terry Porter.

The Suns never finished below 17th in the league in Defensive Rating the last four years; they're 24th so far in 2008-09 and weakened their defense in the deal for Richardson. Brandon Roy's 52-point effort was primarily interpreted as a sign of his own brilliance (including here), but it also exposed Phoenix's glaring lack of a wing stopper sans Raja Bell. Ginobili and Parker could be in for big days in a game that figures to be higher scoring than past Suns/Spurs clashes.

The day's marquee game is the middle matchup of the quintuple-header (a term you don't hear every day), a rematch of last year's NBA Finals. This game has lost a tiny bit of luster with the Lakers struggling over the last two weeks, but Boston has a chance to put a 19-game winning streak on the line by taking care of business at home against Philadelphia tonight. Since a relatively slow start (and certainly 8-2, even without a great point differential, is only a slow start in relative terms), the Celtics have been drilling teams by 14.1 points a night during the streak.

The surprising aspect of Boston's performance has been how well the team has played offensively. Even en route to the title, the Celtics ranked 10th in the NBA in Offensive Rating a year ago. The improvement can largely be traced to Rajon Rondo's emergence as one of the league's top point guards and as valuable a player as any member of the Big Three. I'm still not sure I'm ready to say this year's Boston squad is better than the champs (a question that Paul Flannery used my analysis to help address not long ago on WEEI.com), but this is a more balanced team.

On the other side, the Lakers' story seems well trod by this point. Behind their unconventional defense, they came out of the gate very quickly and established themselves as the early favorites. Starting with their early-December road trip, the Lakers began to struggle on defense, a trend which has not yet abated. They've been able to beat several lesser opponents with subpar efforts, but saw that catch up to them last weekend, dropping consecutive games at Miami and Orlando. Let's update a chart I ran a couple weeks ago looking at the Lakers' defense over the course of the season, which tells a more revealing story than their overall fourth ranking in Defensive Rating.

The overall rating to date makes clear the inexorable rise in the Lakers' Defensive Rating over the course of the year. What is interesting and new from the last chart I did is the Lakers have actually mixed in some pretty good defensive outings (in wins over Milwaukee and Minnesota at home as well as the loss to the Heat that can be explained by a rash of turnovers) in with the dismal ones, with little if any middle ground. In part, the Lakers' defensive struggles can be explained by growing opponent familiarity with the strong-side trap, but it's become increasingly clear that this is also in large part an issue of focus and execution. We know the Lakers have the tools to defend; they've got to stop talking about it and start doing it.

Certainly, focus and motivation should not be an issue in this game, which has been circled on calendars in L.A. since the schedule was released. However, the Celtics will present a major challenge to a Lakers defense that has particularly struggled to contain dribble penetration. That's the strength of Rondo's game, and he's got plenty of finishers to set up when (and if) the help comes. It will also be interesting to see how the teams match up. Doc Rivers doesn't have the same kind of options in going small he had with James Posey during the Finals, while the Lakers are playing much bigger lineups now than in June because of the return of Andrew Bynum.

There's only so much meaning that can be ascribed to an interconference game in December, but this should be a highly entertaining matchup worth every bit of the hype attached to it.

If you're planning your schedule around the NBA (and if not, why on Earth not?), this would be the time to plan dinner. The schedule-makers saw one of the league's most intense rivalries, contested in the first round of the playoffs three straight years, and reasonably expected a good game. Alas, Cleveland and Washington have traveled rapidly in opposite directions since the Cavaliers finished their series victory last spring. Now Cleveland has a legitimate claim to the honorary title of league's best team in December, while the Wizards are already thinking lottery.

Things look especially lopsided when Cleveland has the ball. With Zydrunas Ilgauskas finding the fountain of youth and Delonte West and Mo Williams spreading the floor around LeBron James, the Cavaliers continue to boast the league's best offense. Meanwhile, the Wizards have struggled to stop anyone without injured incumbent center Brendan Haywood and have returned to the league's cellar defensively, a spot they held in 2006-07 as well.

Alas, things won't get much better on the other end of the floor. Cleveland is every bit as stout defensively as it is potent offensively, while Washington has missed both Haywood and Gilbert Arenas on the offensive end of the floor. Surprisingly, newly-acquired Mike James has given the Wizards some decent minutes at the point, averaging 11.2 points and 2.8 assists in six games in Washington. However, the Wizards have yet to get much of a look at sophomore combo guard Javaris Crittenton, the centerpiece of the three-team deal that included James. Crittenton has played just 19 minutes over four games since the deal.

Putting the numbers together for the Blazers made me think of a comparison that had previously gone unrecognized. Portland's rankings are highly similar to a recent team which was third in the league in Offensive Rating, 25th in Defensive Rating and played the league's 27th-fastest pace. That team was the 2004-05 Seattle SuperSonics, coached by Nate McMillan, and while McMillan has very different personnel now in Portland, he has his charges playing a similar style marked by a high number of three-pointers and offensive rebounds. That Sonics team won the Northwest Division and advanced to the second round of the playoffs, giving the eventual champions (San Antonio) a good run before bowing out.

For a decent team, the Mavericks are oddly lacking in compelling storylines this season. The most attention Dallas has received has been for insider trading charges against owner Mark Cuban and for a player the Mavericks traded away--rising star Devin Harris. The Mavericks certainly aren't a bad team, but it's hard to see them legitimately contending in the Western Conference, and if the season ended today they would be the odd team out amongst the nine squads competing for eight spots in the West playoffs. The rankings back up Dallas' maddening lack of an identity; in every single major category, the Mavericks rank between 12th and 14th, just barely above average.

Dallas did attempt something interesting over the summer, looking to take advantage of the "second draft"--a term coined by John Hollinger to describe acquiring players who came into the league at a young age and were unable to find a home with their first team. The theory goes that guys like Gerald Green and Shawne Williams (not unlike Brandon Bass a year ago) are young enough to have plenty of upside, but come cheaply.

While Bass paid off handsomely last year, this season the Mavericks seem to have struck out. Bass has been unable to match his previous effectiveness, proving a liability on the glass and seeing his shooting percentage plummet. Green got off to a solid start, showing newfound long-distance shooting, but has since cooled badly. Williams, meanwhile, has scarcely played. Partially as a result, a Dallas team famous for its depth as recently as two years ago is now disturbingly thin; just four Mavericks (Erick Dampier, Jason Kidd, Dirk Nowitzki and Jason Terry) have been worth more than a half a win above replacement player so far this season, and six Dallas players who have logged occasional playing time rate as below replacement level (Bass, Green, Williams, Devean George, Jerry Stackhouse and Antoine Wright). By contrast, six Blazers (all starters save Nicolas Batum plus reserves Rudy Fernandez and Joel Przybilla) have topped 1.5 WARP, and just two (Jerryd Bayless mostly in garbage time and Channing Frye) have been below replacement level.

Kevin Pelton is an author of Basketball Prospectus.
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